CODEWITHSUNDEEP
javajavascript
lata
lata

Reputation: 1605

Difference between request.getSession().getId() and request.getSession(false)?

What do these calls actually mean in terms of session?

System.out.println("print1: "+request.getSession().getId());
System.out.println("print2: "+request.getSession(false));

OUTPUT

print1: D94146A347D95563186EB7525726336B
print2: org.apache.catalina.session.StandardSessionFacade@d52411

Upvotes: 27

Views: 88021

Answers (8)

Crawling
Crawling

Reputation: 87

request.getSession().getId();

returns the unique identifier assigned to this session. And It has return type of String.

request.getSession(false)

returns the HttpSession object if it already exists else return null.

Upvotes: 0

Suresh
Suresh

Reputation: 518

    request.getSession()

This method will check for the existing session;if exist its return otherwise create a new session for the request.

    request.getSession().getId();

This will return the unique identifier for that session.

    request.getSession(false);

This method takes the boolean value.This method check whether there is an existing session present for that user(request);if exist it return that session otherwise it return null i.e it won't create new session.

Just to add more information for session.

    request.getSession(true);

This method checks for the existing current session for that user(request) and if the session exist it will return that session or otherwise it create new session for that user.

    request.getSession() works like request.getSession(true)

Reference : http://docs.oracle.com/javaee/1.4/api/javax/servlet/http/HttpServletRequest.html#getSession%28boolean%29

Upvotes: 4

a bouchenafa
a bouchenafa

Reputation: 272

request.getSession().getId();

this will return the id of the an existing session.

Request.getsession(false)

it will return the session if it exists, or it will return null otherwise.

and Request.getsession(false) means : give me the session if it exists, otherwise do not create a new instance (and thus return null).

Upvotes: 0

Manish Nagar
Manish Nagar

Reputation: 1046

HttpSession session = request.getSession(); Inside the service method we ask for the session and every thing gets automatically, like the creation of the HttpSession object. There is no need to generate the unique session id. There is no need to make a new Cookie object. Everything happens automatically behind the scenes.

As soon as call the method getSession() of the request object a new object of the session gets created by the container and a unique session id generated to maintain the session. This session id is transmitted back to the response object so that whenever the client makes any request then it should also attach the session id with the requsest object so that the container can identify the session.

request.getSession(false) : This method will check whether Session already existed for the request or not. If it existed then it will return the already existed Session. If Session is not already existed for this request then this method will return NULL, that means this method says that the request does not have a Session previously.

Upvotes: 20

Rais Alam
Rais Alam

Reputation: 7016

request.getSession().getId();

Will return unique string id assigned to already started session. Generation of id is vendor specific like apache, jboss etc.

request.getSession(false);

It will return session object associated to particular request if session object is associated it will be returned or it will return null if its is not started by server.

Upvotes: 1

Subhrajyoti Majumder
Subhrajyoti Majumder

Reputation: 41200

In short-

request.getSession().getId() - returns a string containing the unique identifier assigned to this session. The identifier is assigned by the servlet container and is implementation dependent.

request.getSession(false) - return session object or null if there's no current session.

Upvotes: 17

Mukul Goel
Mukul Goel

Reputation: 8467

request.getSession().getId()

Returs the id of the session.

Request.getsession(false) returns the already existing session object. It wont return anything i.e. Will return null , if session does not exist. Whereas with true parameter it will create a new session object and return it if no session exists

Upvotes: 2

Lukasz Zuchowski
Lukasz Zuchowski

Reputation: 258

First line will return the "session id" on server. The second line will return session object. So what will be printed on system.out would be request.getSession(false).toString();

The default implementation of toString returns the "object id". Object id in terms of session is not the same as session id. Session could be serialized and replicated across the cluster so on each node of the cluster on each JVM it may have it's own object id (but should have same session id).

Calling get session with boolean is explained here: http://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html#getSession(boolean)

Upvotes: 5

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